Multimode apparatus and method for making same

ABSTRACT

An apparatus operable in touch-input mode and scanning mode uses a light guide and a camera to look through a slanted facet at one corner of the light guide. The light guide has an upper surface for placing a touch object or an item for scanning. An angular sensitive grating is located on lower surface having fringes such that when a light beam directed from a location P on upper surface toward lower surface at a predefined direction, it is diffracted by the grating and guided toward the slanted facet. The diffracted beam exits the slanted facet at an exiting angle indicative of the location P. When an object or item is placed on upper surface, it causes changes in exit beam intensity. From exiting angles and intensity changes, a camera is able to locate touch objects or to acquire an image of the scanned item.

The present application claims the benefit of a U.S. Provisional PatentApplication, Ser. No. 61/004,834, filed Nov. 30, 2007.

FIELD OF THE INVENTION

The present invention relates generally to a multimode apparatus and,more particularly, to a multimode apparatus that can be used as a touchinput device in one mode and as a scanning device in another mode.

BACKGROUND OF THE INVENTION

Some electronic devices require an input device, such as a touch pad,for inputting graphical information. Typically a touch pad has a surfacefor allowing a user to touch the surface at one or more locations.Various sensing technologies have been developed to sense the touchlocations.

It is desirable and advantageous to provide a multimode apparatus thatcan be used as an input device and as a scanning device, for example.

SUMMARY OF THE INVENTION

The present invention provides an apparatus operable in a touch-inputmode and in a scanning mode. The apparatus uses a light guide having afirst surface and a second surface, and a camera or optical sensingmodule to look into the light guide for providing signals indicative ofwhat the camera sees on the first surface on the light guide. The lightguide has a slanted facet at one of its corners. The light guide has adiffractive element located on the second surface. The diffractiveelement has one or more diffractive structures with a plurality ofconcentric fringes centered at that corner. The concentric fringes forman angular sensitive grating, such that when a light beam is directedfrom a location P on the first surface toward the second surface along apre-defined direction or angle, the light beam is diffracted toward thefirst surface and guided in the light guide unit it exits throughslanted facet at an exiting angle into the camera. The exiting angle canbe used to determine the distance between the location P and a referencepoint near the corner. When an object is placed on the first surface, itmay change the intensity of the exit beam. Based on the angularsensitive nature of the grating and the intensity change in the exitbeam, the camera is able to detect the presence of a touch object whenthe apparatus is operated in the touch-input mode. Similarly, when adocument is placed facedown on the first surface, the intensityvariation is indicative of the text or drawing on the document in thescanning mode.

Thus, the first aspect of the present invention is an apparatus operablein a touch-input mode and in a scanning mode. The apparatus uses a lightguide having a first surface and a second surface to allow a user toinput information from the first surface when the apparatus is operatedin the touch-input mode or to place an item for scanning when theapparatus is operated in the scanning mode. The second surface has anangular sensitive grating to diffract a light beam that is directed fromthe first surface toward the second surface at a pre-defined angle ordirection. The diffracted beam is guided in the light guide andsubsequently exits the light guide at an exiting angle through a slantedfacet at one corner of the light guide. The exiting angle allows acamera to determine the distance of a touch object to a reference pointbased on the diffracted beam. When the apparatus is used in the scanningmode, the image of the scanned item placed on the first surface isacquired by the camera and analyzed by a processor.

In an embodiment of the first aspect of the invention, an apparatuscomprises a light guide having a first surface and an opposing secondsurface, an optical sensing module for sensing light from the lightguide and providing signals indicative of a light beam emerging from thelight guide between the first surface and the second surface, and aprocessor, operatively connected to the optical sensing module, fordetecting intensity variation in the light beam based on the signals,wherein the apparatus is operable in a first mode and a second mode, andwherein when the apparatus is operated in the first mode, the intensityvariation is indicative of placing of one or more objects at the firstsurface, and when the apparatus is operated in second mode, theintensity variation is indicative of content on an item placed on thefirst surface.

In an embodiment of the first aspect of the invention, the light guidecomprises a slanted facet located at a corner of the light guide, theslanted facet extending at least from the first surface toward thesecond surface, and a diffractive element provided on the secondsurface, the diffractive element comprising a plurality of fringesarranged such that when the light beam is directed from a location onthe first surface toward the second surface at a predefined direction,the light beam is diffracted toward the first surface and guided in thelight guide and subsequently exits the light guide through the slantedfacet as an exit beam at an exiting angle, the exiting angle indicativeof a distance between the location and a reference point at the corner.

In an embodiment of the first aspect of the invention, when an object ispresent at the location on the first surface, intensity of the exit beamis caused to change, and wherein the optical sensing module isconfigured for detecting the exit beam having the exiting angle and thechange in the intensity of the exit beam, and the signals provided tothe processor are indicative of the exiting angle and the change in theintensity of the exit beam, the processor configured for detectingpresence of the object at the location and determining the distance fromthe location to the reference point based on the signals.

In an embodiment of the first aspect of the invention, the apparatusalso includes a light source for providing illumination to the firstsurface, so as to allow the optical sensing module to detect presence ofone or more objects at one or more locations on the first surface.

In an embodiment of the first aspect of the invention, the opticalsensing module comprises a camera optically coupled to the slantedsurface.

In an embodiment of the first aspect of the invention, when theapparatus is operated in the first mode, the processor is configured fordetermining presence of the one or more objects at one or more locationson the first surface.

In an embodiment of the first aspect of the invention, the processor isconfigured for determining the one or more locations in a time sequenceso as to detect changes in the one or more locations responsive tomovement of the one or more objects.

In an embodiment of the first aspect of the invention, the movement ofthe one or more objects is indicative of an input character, and theapparatus also includes a handwriting character recognition module fordetermining the input character based on the movement.

In an embodiment of the first aspect of the invention, the movement ofthe one or more objects is indicative of a tracking, and the processoris configured for determining a gesture or a sketch defined by thetracking.

In an embodiment of the first aspect of the invention, the predefineddirection is substantially perpendicular to the second surface.

In an embodiment of the first aspect of the invention, when theapparatus is operated in the second mode, the processor is configuredfor detecting intensity variations in light directed from a plurality oflocations on the first surface, and for determining the content on theitem based on the intensity variations.

In an embodiment of the first aspect of the invention, the processor isconfigured for forming an image of the content on the item.

In an embodiment of the first aspect of the invention, the apparatusalso includes a memory module for storing the image.

In an embodiment of the first aspect of the invention, the contentcomprises text having text characters, and the apparatus also includesan optical character recognition module for recognizing the characters.

In an embodiment of the first aspect of the invention, the apparatusalso includes a display for displaying the image.

In an embodiment of the first aspect of the invention, the itemcomprises a substrate and the content comprises pigment areasdistributed on the substrate, and the processor is configured to recordthe pigment areas on the substrate.

In an embodiment of the first aspect of the invention, the apparatusalso includes a sensor for sensing the item placed on the first surface,the sensing module causing the apparatus to operate in the second modebased on the sensing.

In an embodiment of the first aspect of the invention, the apparatuscomprises a mobile terminal.

The second aspect of the present invention is a method for operating anapparatus in a touch-input mode and in a scanning mode. The methodcomprises:

providing a light guide having a first surface and an opposing secondsurface;

providing an optical sensing module in relationship to the light guidefor sensing light from the light guide and for providing signalsindicative of a light beam emerging from the light guide; and

providing the signals to a processor, the processor configured fordetecting intensity variation in the light beam based on the signals,wherein when the apparatus is operated in the touch-input mode, theintensity variation is indicative of placing of one or more objects onthe first surface, and when the apparatus is operated in the scanningmode, the intensity variation is indicative of content on an item placedon the first surface. The light guide comprises a slanted facet locatedat a corner of the light guide, the slanted facet extending at leastfrom the first surface toward the second surface, and the opticalsensing module is located at the slanted facet. The light guide has adiffractive element located on the second surface, the diffractiveelement comprising a plurality of fringes arranged such that

when the light beam is directed from a location P on the first surfacetoward the second surface at a selected or predefined direction, thelight beam is diffracted by the diffractive element toward the firstsurface and guided by the light guide until it exits the light guidethrough the slanted facet at an exiting angle indicative of a distancebetween the location P and a reference point at the corner.

The light guide is arranged such that when an object is present at alocation on the first surface, the intensity of the exit beam is causedto change, and the optical sensing module is configured for detectingthe exit beam having the exiting angle and the intensity change in theexit beam. Based on the exiting angle and the intensity change in theexit beam, the processor is able to determine the location and presenceof the object at the location.

When the apparatus is operated in the touch-input mode, the processor isconfigured for determining the presence of one or more objects at one ormore locations on the first surface. The one or more locations can bedetected in a time sequence so as to detect the movement of the one ormore objects.

When the apparatus is operated in the scanning mode, the light beam isindicative of intensity variations in light directed from a plurality oflocations on the first surface, and the signals are indicative of theintensity variations. The processor is configured to determine thecontent of the item based on the signals and to form an image of thecontent of the item.

In an embodiment of the second aspect of the invention, the methodcomprises providing a light guide in an apparatus operable in a firstmode and in a second mode, the light guide having a first surface and anopposing second surface, optically coupling an optical sensing module tothe light guide for sensing light from the light guide and for providingsignals indicative of one or light beams emerging from the light guidebetween the first surface and the second surface, and providing thesignals to a processor, the processor configured for detecting intensityvariation in the one or more light beams based on the signals, whereinwhen the apparatus is operated in the first mode, the intensityvariation is indicative of placing of one or more objects on the firstsurface, and when the apparatus is operated in second mode, theintensity variation is indicative of content on an item placed on thefirst surface.

In an embodiment of the second aspect of the invention, the light guidecomprises a slanted facet located at a corner of the light guide, theslanted facet extending at least from the first surface toward thesecond surface, and the optical sensing module is optically coupled tothe slanted facet, and the method further includes providing adiffractive element on the second surface, the diffractive elementcomprising a plurality of fringes arranged such that when the light beamis directed from a location on the first surface toward the secondsurface at a predefined direction, the light beam is diffracted by thediffractive element toward the first surface and guided in light guide,and the diffracted light beam exits the slanted facet as an exit beam atan exiting angle, the exiting angle indicative of a distance between thelocation and a reference point at the corner.

In an embodiment of the second aspect of the invention, when an objectis present at the location on the first surface, intensity of the exitbeam is caused to change, and wherein the optical sensing module isconfigured for detecting the exit beam having the exiting angle and thechange in the intensity of the exit beam, and the signals provided tothe processor are indicative of the exiting angle and the change in theintensity of the exit beam, and the method further includes configuringthe processor to determine the location and presence of the object atthe location based on the signals.

In an embodiment of the second aspect of the invention, when theapparatus is operated in the first mode, the processor is configured fordetermining presence of the one or more objects at one or more locationson the first surface.

In an embodiment of the second aspect of the invention, the methodfurther includes configuring the processor to determine the one or morelocations in a time sequence so as to detect changes in the one or morelocations responsive to movement of the one or more objects, anddetermining the movement of the one or more objects.

In an embodiment of the second aspect of the invention, when theapparatus is operated in the second mode, the light beam is indicativeof intensity variations in light directed from a plurality of locationson the first surface, and the signals are indicative of the intensityvariations, and the method further includes configuring the processorfor determining the content of the item based on the signals and forforming an image of the content of the item.

In an embodiment of the second aspect of the invention, the contentcomprises text having text characters, and the method further includesrecognizing the text characters.

The present invention will become apparent upon reading the descriptiontaken in conjunction with FIGS. 1 to 7.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top-view of the input device, according to one embodimentof the present invention.

FIG. 2 shows a side view of the input device.

FIG. 3 shows a light beam for illuminating the input device.

FIG. 4 shows an image having a spot resulting from a touch object on thedevice surface.

FIG. 5 shows a processor for determining the coordinate of the touchobject.

FIG. 6 is a schematic representation of a multimode apparatus, accordingto one embodiment of the present invention.

FIG. 7 shows an exemplary architecture of the multimode apparatus,according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The multimode apparatus, according to various embodiments of the presentinvention, comprises an input device for gathering input information andone or more processors for processing the information. The input devicecomprises mainly a light guide and an optical sensing module coupled toa light guide. The light guide has a touch surface to allow a user toplace an object on the touch surface at a location and the opticalsensing module is configured to determine the touch location inrelationship to a reference point. The optical sensing module, alongwith a process, can be used to track the touch location as a function oftime. The movement of the touch location may be indicative of a gesture,a drawing or a handwritten character. The gesture or the handwrittencharacter may be recognized using a handwriting character recognitionmodule or a software program based on the movement.

The same light guide can be used for scanning a document, a picture orthe like that is placed facedown on the light guide. The optical sensingmodule, along with the processor, can be used to acquire an image of thescanned document or picture, and store the image in a storage device. Ifthe document or picture is larger than the surface of the light guide,the document may need to be scanned a number of times. Image stitchingor image mosaic technique can be used to form the image of a fulldocument, for example. Image layout analysis and pre-segmentation may beperformed on the image to yield a preliminary processing result. Anoptical character recognition module can be used to recognize the texton the documents. The recognition process may include iterativecharacter segmentation and recognition. That is, segmentation is forcharacter recognition and the recognition result can be used to correctsegmentation errors and to update previous recognition results.

In the touch-input mode as well as the scanning mode, language modelsand electronic dictionaries can be used to correct the recognizedcharacters based on language syntax, language grammar, language habitsand so on. The recognized characters or text can be displayed on adisplay panel so that the user can verify the characters and providefeedback on wrong recognition to the system so that the system canprocess the wrong recognition again. Part or all of the language models,electronic dictionaries, character recognition program can be embeddedin one or more computer readable storage media.

An exemplary input device for use in the multimode apparatus is shown inFIG. 1. The input device 1, according to one embodiment of the presentinvention, includes a light guide 10 and an optical sensing module, suchas a camera 50 located at one corner of the light guide. The camera 50is used to determine the location of a touch object placed on or nearthe surface of the light guide. As shown in FIG. 1, the location at apoint (x, y) can be determined by the angle φ and the distance r:x =rsinφ,y =rcosφThe light guide 10 has a diffractive element or one or more diffractivestructures made of substantially concentric fringes centered at a pointnear or at the camera 50. The center of the concentric fringes can belocated at a point of the camera aperture, for example, and used as areference point for determining the distance r. One of the functions ofthe diffractive structures is to allow the camera to determine r.

As shown in FIG. 2, the light guide 10 has a first surface 12 used as atouch input surface, and a second surface 14 for implementing thediffractive structures 30. The light guide 10 also has a slanted facet16 extending from the first surface toward the second surface. Theplacement of the camera or optical sensing module 50 at the slantedfacet 16 allows the camera 50 to “peer into” the light guide 10 throughthe slanted facet 16. In particular, the camera 50 is configured to seea large area of the first surface 12 from the inside of the light guide10. As such, the camera 50 is able to detect one or more touch objectsat one or more touch locations on the first surface 12.

According to one embodiment of the present invention, the concentricfringes in the diffractive structures 30 form an angular sensitivegrating, such that a light beam directed from a location P on the firstsurface to another point on the second surface is more significantlydiffracted toward the first surface by the diffractive structures 30only when the beam counters the diffractive structures 30 at apredefined angle or direction. The diffracted beam may be reflected bythe first surface a number of times before it exits through the slantedfacet 16 an exiting angle θ. For example, the beam that encounters thediffractive structures 30 at a 90 degree angle (or the beam direction issubstantially perpendicular to the second surface) will be significantlydiffracted and form an exiting beam, as shown in FIG. 2. The concentricfringes are arranged such that the exiting angle θ is related to thedistance between the location P and the corner. As the distance is afunction of the exiting angle θ, a light beam enters or directed fromthe first surface at a different distance will exit the slanted facet 16at a different exiting angle θ. The camera 50 placed adjacent to theslanted facet 16 is configured to determine the distance of thedirecting point P at least partly based on the exiting angle θ. Becausethe fringes are concentric about a point at the corner, the exitingangle θ does not vary with φ. Thus, the distance r can be determined byθ and the thickness of the light guide 10, for example. From the angularinformation in θ and φ, the camera 50 is able to determine the locationof light directing point P on the first surface 10. Thus, the presentinvention uses the transformations (θ, φ)→(r, φ) and (r, φ)→(x,y) todetermine the location of a touch event.

According to various embodiments of the present invention, the camera 50is also configured to obtain the intensity of an exiting beam. When anobject is present at a point P, the amount of light directed at thatpoint may change. Thus, the optical sensing module or camera 50 is ableto determine a touch event and the touch location from the change in theintensity of the exit beam.

In one embodiment of the present invention, a light source having abroad light beam 90 is provided to illuminate the light guide 10 throughthe second surface 14 and the diffractive structures 30, as shown inFIG. 3. When the first surface 12 is not touched by any object, thecamera 50 will see a blank image indicative of a distribution of lightintensity partly resulting from the reflection of the light beam 90 bythe first surface 12. When an object is present at the first surface,for example, a spot S would appear in the blank image 55, as shown inFIG. 4. The brightness or darkness of the spot is determined by thecolor, and the surface characteristics of the touch object. For example,if the touch object is white, highly reflective or light emitting, thespot is brighter than other areas of the image. If the touch object isblack or light absorbing, the spot could be dark.

Furthermore, the optical sensing module or camera 50, along with aprocessor 70 (see FIG. 5), can be configured to obtain the coordinates(x,y) of a touch object based on the exiting angle of the exit beam orthe location of the spot S on the image 55.

In general, when a document is placed facedown on the first surface, forexample, the drawing or text on the document also causes the change inthe intensity of the exit beam. In order for the optical sensing module50 to see a large part of the document covering the first surface, alight source is placed adjacent to the second surface to provide a broadlight beam so that reflection from a large area of the first surface canbe observed by the optical sensor module 50. In an indirect way, thebroad light beam illuminates the document covering the first surfacethrough the diffraction by the diffractive structure on the secondsurface. By detecting the light intensity at various reflectionlocations on the first surface, the optical sensing module is able toform an image of the document covering the first surface.

The placement of the optical sensing module in relationship to theslanted facet 16 allows the optical sensing module to “look into” theinside of the light guide 10. With a broad light beam illuminating thefirst surface and the objects placed on the first surface from theoutside of the light guide, the optical sensing module is able to seethe reflection from a large part of the first surface and form an imageof the objects or a document placed on the first surface.

Accordingly, the input device 1 can be used as a touch input device andas a scanning device. By using such an input device, the multimodeapparatus is operable at least in two modes: a first mode as a touchinput device and a second mode as a scanning device. The optical sensingmodule can be coupled to a processor so that the coordinates (x, y) ofone or more touch objects can be computed and an image of a scanneddocument can be obtained.

The multimode apparatus, according to one embodiment of the presentinvention, comprises a light source for illumination. As shown in FIG.6, the multimode apparatus 100 has a light source 20 with a broad lightbeam to illuminate the light guide 10 through the second surface 14 andthe diffractive structures 30. Instead of placing the optical sensingmodule or camera 50 directly adjacent to the slanted facet 16 as shownin FIG. 2, a light reflector or deflector 40 can be used to direct thelight beam exiting the slanted facet 16 to the optical sensing module50. As such, the optical sensing module 50 will not obstruct thescanning operation. In one embodiment of the present invention, themultimode apparatus has a switch (not shown) or the like to allow a userto choose between a touch-input mode and a scanning mode. Alternatively,a sensing device 42 is placed near the first surface 10 to detectwhether a document 200 or the like is covering the first surface forscanning.

The optical sensing module or camera 50, along with a processor 70 canbe configured to obtain the touch locations when the multimode apparatus100 is operated in the touch-input mode. The optical sensing module 50can be configured to detect the touch locations in a time sequence. Assuch, the optical sensing module is able to detect the movement of thetouch object or objects. The movement of a touch object may beindicative of a drawing by a user using the touch object as a drawingtool. The movement can be indicative of a gesture. The processor 70 mayinclude a software program for drawing recognition, a software programfor handwriting recognition, and so on (see FIG. 7). When the multimodeapparatus 100 is operated in the touch-input mode, it is possible to usean infrared light source in the vicinity of the camera aperture or otherlocations to illuminate the touch objects, for example. As such, thetouch-input mode can be used under ambient light and the optical sensingmodule 50 is configured for detecting the changes in the infra red lightat various locations on the first surface 12. The touch locations or thedrawing or gesture can be displayed on a display panel 75, for example.

When the multimode apparatus 100 is operated in the scanning mode, theimage formed by the optical sensing device can be stored in a memory 80and displayed on the display panel 75, for example. The processor 70 mayhave a software program for text image stitching and layout analysis.This function is useful when the scanned document is larger than thefirst surface 12 of the light guide 10 and it may be necessary to scan aportion of the document at a time. The processor 70 may have an opticalcharacter recognition software program for character recognition(Chinese, Latin, Japanese, Greek, etc.). After the scanned charactersare recognized, a language-processing module can be used to correct therecognized characters based on language syntax, language grammar and soon. The language-processing module may have one or more language modulesand dictionaries.

In the scanning mode, the optical sensing device can be used to read orrecord a document, a drawing, a picture, a barcode, a business card, andan identification card to be authenticated, for example. Any one of theabove-listed items can be generalized as a substrate having adistribution of pigment areas on the substrate surface. For example, ifthe scanned item is a line drawing on a piece of paper in red ink, thenthe paper is the substrate, and the drawing can be viewed as having anamount of red pigment distributed along the drawing line or lines.

In sum, the present invention provides an apparatus operable in atouch-input mode and a scanning mode, the apparatus comprises:

a light guide having a first surface and an opposing second surface forguiding light at least between the first surface and the second surface;

an optical sensing module for sensing light from the light guide andproviding signals indicative of a light beam emerging from the lightguide; and

a processor, operatively connected to the optical sensing module, fordetecting intensity variation in the light beam based on the signals,wherein when the apparatus is operated in the touch-input mode, theintensity variation is indicative of placing of one or more objects onthe first surface, and when the apparatus is operated in scanning mode,the intensity variation is indicative of the content on an item placedon the first surface for scanning.

According to one embodiment of the present invention, the light guidecomprises:

a slanted facet located at a corner of the light guide, the slantedfacet extending at least from the first surface toward the secondsurface, wherein the optical sensing module is located at the slantedfacet; and

a diffractive element located on the second surface, the diffractiveelement comprising a plurality of fringes arranged such that

when the light beam is directed from the first surface at a location Ptoward the second surface at a selected or predefined direction, thelight beam is diffracted by the diffractive element toward the firstsurface and is guided in the light guide until it exits the light guidethrough the slanted facet as an exit beam with an exiting angle, theexiting angle indicative of a distance between the location P and areference point at the corner. The predefined direction is substantiallyperpendicular to the second surface, for example.

In the apparatus, the light guide is arranged such that when an objectis present at a location on the first surface, the intensity of the exitbeam is caused to change, and the optical sensing module is configuredfor detecting the exit beam having the exiting angle and the change inthe intensity of the exit beam, and the signals provided to theprocessor are indicative of the exiting angle and the change in theintensity of the exit beam. Based on the signals, the processordetermines the presence of the object at that location.

The apparatus may have a light source for providing illumination to thefirst surface, so as to allow the optical sensing module to detect thepresence of one or more objects at one or more locations on the firstsurface. The optical sensing module can be a camera having an aperture,and the reference point can be located at the aperture, for example.

When the apparatus is operated in the touch-input mode, the processor isconfigured for determining the presence of the one or more objects atone or more locations on the first surface in a time sequence so as todetect the movement of the one or more objects.

According to one embodiment of the present invention, the movement ofthe one or more objects is indicative of an input character, and theapparatus further comprises a handwriting character recognition modulefor determining the input character based on the movement. The movementcan also be indicative of a gesture or a sketch.

According to one embodiment of the present invention, when the apparatusis operated in the scanning mode, the light beam is indicative ofintensity variations in light directed from a plurality of locations onthe first surface, and the signals are indicative of said intensityvariations. Based on the signals, the processor determines the contenton the item, and forms an image of the item. The image can be stored ina memory module and/or displayed on a display panel, for example. Whenthe item is a document containing text as its content, the apparatusalso has an optical character recognition module for recognizingcharacters in the text.

According to one embodiment of the present invention, the item is apicture, and the processor is configured to record the picture.

According to one embodiment of the present invention, a sensor can beused to sense the item placed on the first surface for scanning, and thesensor can cause the apparatus to operate in the scanning mode when theitem is present.

The present invention also provides a method for operating an apparatusin a touch-input mode and in a scanning mode. The method comprises:

providing a light guide having a first surface and an opposing secondsurface;

providing an optical sensing module in relationship to the light guidefor sensing light from the light guide and for providing signalsindicative of a light beam emerging from the light guide; and

providing the signals to a processor, the processor configured fordetecting intensity variation in the light beam based on the signals,wherein when the apparatus is operated in the touch-input mode, theintensity variation is indicative of placing of one or more objects onthe first surface, and when the apparatus is operated in scanning mode,the intensity variation is indicative of the content on an item placedon the first surface for scanning. The light guide comprises a slantedfacet located at a corner of the light guide, the slanted facetextending at least from the first surface toward the second surface, andthe optical sensing module is located at the slanted facet. The lightguide has a diffractive element located on the second surface, thediffractive element comprising a plurality of fringes arranged such that

when the light beam is directed from the first surface at a location Ptoward the second surface at a predefined direction, the light beam isdiffracted by the diffractive element toward the first surface. Thediffracted beam is guided in the light guide and subsequently exits thelight guide through the slanted facet as an exit beam at an exitingangle, the exiting angle indicative of a distance between said locationand a reference point at said corner. The predefined direction issubstantially perpendicular to the second surface, for example.

The apparatus can be a stand-alone device, or integrated into a mobilephone or the like. The fringes on the diffractive element or structurescan be interference fringes or grooves on a surface.

Thus, although the present invention has been described with respect toone or more embodiments thereof, it will be understood by those skilledin the art that the foregoing and various other changes, omissions anddeviations in the form and detail thereof may be made without departingfrom the scope of this invention.

What is claimed is:
 1. An apparatus, comprising: a light guide having afirst surface and an opposing second surface, comprising: a facetextending at least from the first surface toward the second surface, anda diffractive element provided on the second surface, the diffractiveelement comprising a plurality of fringes arranged such that when thelight beam is directed from a location on the first surface toward thesecond surface at a redefined direction, the light beam is diffractedtoward the first surface and guided in the light guide and subsequentlyexits the light guide through the facet as an exit beam at an exitingangle, the exiting angle being indicative of a distance between saidlocation and a reference point; an optical sensing module for sensinglight from the light guide and providing signals indicative of a lightbeam emerging from the light guide between the first surface and thesecond surface; and a processor, operatively connected to the opticalsensing module, for detecting intensity variation in the light beambased on the signals, wherein the apparatus is operable in a first modeand a second mode, and wherein when the apparatus is operated in thefirst mode, the intensity variation is indicative of placing of one ormore objects at the first surface, and when the apparatus is operated insecond mode, the intensity variation is indicative of content on an itemplaced on the first surface.
 2. The apparatus of claim 1, wherein thethe facet is a slanted facet located at a corner of the light guide, andsaid reference point is located at said corner.
 3. The apparatus ofclaim 2, wherein when an object is present at said location on the firstsurface, intensity of the exit beam is caused to change, and wherein theoptical sensing module is configured to detect the exit beam having theexiting angle and the change in the intensity of the exit beam, and thesignals provided to the processor are indicative of the exiting angleand the change in the intensity of the exit beam, the processorconfigured to detect presence of the object at said location anddetermining the distance from said location to the reference point basedon the signals.
 4. The apparatus of claim 3, further comprising a lightsource for providing illumination to the first surface, so as to allowthe optical sensing module to detect presence of one or more objects atone or more locations on the first surface.
 5. The apparatus of claim 2,wherein the optical sensing module comprises a camera optically coupledto the slanted surface.
 6. The apparatus of claim 3, wherein when theapparatus is operated in the first mode, the processor is configured todetermine presence of the one or more objects at one or more locationson the first surface.
 7. The apparatus of claim 6, wherein the processoris configured to determine the one or more locations in a time sequenceso as to detect changes in said one or more locations responsive tomovement of said one or more objects.
 8. The apparatus of claim 2,wherein when the apparatus is operated in the second mode, the processoris configured to detect intensity variations in light directed from aplurality of locations on the first surface, and for determining thecontent on the item based on the intensity variations.
 9. The apparatusof claim 8, wherein the processor is configured to form an image of thecontent on the item.
 10. The apparatus of claim 8, wherein the contentcomprises text having text characters, said apparatus furthercomprising: an optical character recognition module for recognizing thecharacters.
 11. The apparatus of claim 8, wherein the item comprises asubstrate and the content comprises pigment areas distributed on thesubstrate, and the processor is configured to record the pigment areason the substrate.
 12. The apparatus of claim 1, wherein the predefineddirection is substantially perpendicular to the second surface.
 13. Theapparatus of claim 1, further comprising: a sensor for sensing the itemplaced on the first surface, the sensing module causing the apparatus tooperate in the second mode based on said sensing.
 14. The apparatus ofclaim 1, comprising a mobile terminal.
 15. A method, comprising:providing a light guide in an apparatus operable in a first mode and ina second mode, the light guide having a first surface and an opposingsecond surface comprising a facet extending at least from the firstsurface toward the second surface, and a diffractive element provided onthe second surface, the diffractive element comprising a plurality offringes arranged such that when the light beam is directed from alocation on the first surface toward the second surface at a predefineddirection, the light beam is diffracted toward the first surface andguided in the light guide and subsequently exits the light guide throughthe facet as an exit beam at an exiting angle, the exiting angle beingindicative of a distance between said location and a reference point;optically coupling an optical sensing module to the light guide forsensing light from the light guide and for providing signals indicativeof one or light beams emerging from the light guide between the firstsurface and the second surface; and providing the signals to aprocessor, the processor configured to detect intensity variation insaid one or more light beams based on the signals, wherein when theapparatus is operated in the first mode, the intensity variation isindicative of placing of one or more objects on the first surface, andwhen the apparatus is operated in second mode, the intensity variationis indicative of content on an item placed on the first surface.
 16. Themethod of claim 15, wherein the facet comprises a slanted facet locatedat a corner of the light guide, and the optical sensing module isoptically coupled to the slanted facet, wherein said method comprisesdiffracting the light beam by the diffractive element and guiding thelight beam in light guide, so that the diffracted light beam exits theslanted facet and the exiting angle is indicative of a distance betweensaid location and the reference point at said corner.
 17. The method ofclaim 16, wherein when an object is present at said location on thefirst surface, intensity of the exit beam is caused to change, andwherein the optical sensing module is configured to detect the exit beamhaving the exiting angle and the change in the intensity of the exitbeam, and the signals provided to the processor are indicative of theexiting angle and the change in the intensity of the exit beam, saidmethod further comprising; configuring the processor to determine saidlocation and presence of the object at said location based on thesignals.
 18. The method of claim 17, wherein when the apparatus isoperated in the first mode, the processor is configured to determinepresence of the one or more objects at one or more locations on thefirst surface.
 19. The method of claim 18, further comprising:configuring the processor to determine the one or more locations in atime sequence so as to detect changes in said one or more locationsresponsive to movement of said one or more objects, and determining themovement of said one or more objects.
 20. A method, comprising:providing a light guide in an apparatus operable in a first mode and ina second mode, the light guide having a first surface and an opposingsecond surface; optically coupling an optical sensing module to thelight guide for sensing light from the light guide and for providingsignals indicative of one or more light beams emerging from the lightguide between the first surface and the second surface; and providingthe signals to a processor, the processor configured to detect intensityvariation in said one or more light beams based on the signals, whereinwhen the apparatus is operated in the first mode, the intensityvariation is indicative of placing of one Cr more objects on the firstsurface, and when the apparatus is operated in the second mode, theintensity variation is indicative of content on an item placed on thefirst surface, the light beam is indicative of intensity variations inlight directed from a plurality of locations on the first surface, andthe signals are indicative of said intensity variations, said methodfurther comprising: configuring the processor for determining thecontent of the item based on the signals and for forming an image of thecontent of the item.